HCD-GTR33, HCD-GTR55, HCD-GTR77, MHC-GTR33, MHC-GTR55, MHC-GTR77 - Sony Audio Service Manual (repair manual). Page 11

This mode is used to check the fl uorescent indicator tube, LEDs, 
keys, [MASTER VOLUME] jog, [OPERATION DIAL] jog, mod-
el, destination and software version.
Procedure:
1. Press 

[

x

] button, [METER MODE] button and [DISC SKIP/

EX-CHANGE] button simultaneously.

2.  All LEDs and segments in fl uorescent indicator tube are light-

ed up. 

3.  When you want to enter to the software version display mode, 

press [DISC 1] button. The model information appears on the 
fl uorescent indicator tube.

 

• “GVX 1S”  is shown for MHC-GTR33.

 

• “GVX 3S”  is shown for MHC-GTR55.

 

• “GVX 4S”  is shown for MHC-GTR77.

 

Press [DISC 1] button again to view the destination informa-
tion.

4.  During the destination information display, press [DISC 1] 

button. Each time [DISC 1] button is pressed, the fl uorescent 
indicator tube shows the version of each category software in 
the following sequence: SC, MTK (DMB Board fi rmware ver-
sion), GC, SYS, CD, CDMA, CDMB, ST, TC TA, TM , MTR 
(METER) and return back to model information display.

5.  When [DISC 3] button is pressed while the version numbers 

are being displayed except model and destination, the date 
of the software creation appears. When [DISC 3] button is 
pressed again, the display returns to the software version dis-
play. When [DISC 1] button is pressed while the date of the 
software creation is being displayed, the date of the software 
creation is displayed in the same order of software version dis-
play.

6.  Press [DISC 2] button, the key check mode is activated.
7.  In the key check mode, the fl uorescent indicator tube displays 

“K 0    V0”.

 

Each time a button is pressed, “K” value increases. However, 
once a button has been pressed, it is no longer taken into ac-
count.

 

“V” value increases in the manner of 0,1, 2, 3 ... if [MASTER 
VOLUME] knob is turned clockwise, or it decreases in the 
manner of 0, 9, 8,7  ... if [MASTER VOLUME] knob is turned 
counterclockwise.

8.  When [DISC SKIP/EX-CHANGE] button is pressed after all 

LEDs and segments in fl uorescent indicator tube light up, al-
ternate segments in fl uorescent indicator tube and LEDs would 
light up. If you press [DISC SKIP/EX-CHANGE] button 
again, another half of alternate segments in fl uorescent indi-
cator tube and LEDs would light up.  Pressing [DISC SKIP/
EX-CHANGE] button again would cause all segments in fl uo-
rescent indicator tube and LEDs light up.

9.  To release from this mode, press three buttons in the same 

manner as step 1, or disconnect the power cord.

This mode is used to check operations of the Amplifi er section.

Procedure:
To enter Common Test Mode
1. Press [

x

] button, [METER MODE] button and [OPEN/

CLOSE] button simultaneously.

2.  The CD ring indicators fl ash on the fl uorescent indicator tube. 

The function is changed to AUDIO and the volume is changed 
to VOLUME MIN.

Check of Amplifi er
1.  Press [EQ BAND/SURROUND] button repeatedly until a 

message “GEQ MAX” appears on the fl uorescent  indicator 
tube. GEQ increases to its maximum.

2.  Press [EQ BAND/SURROUND] button repeatedly until a 

message “GEQ MIN” appears on the fl uorescent  indicator 
tube. GEQ decreases to its minimum.

3.  Press [EQ BAND/SURROUND] button repeatedly until a 

message “GEQ FLAT” appears on the fl uorescent  indicator 
tube. GEQ is set to fl at.

4.  When the [MASTER VOLUME] knob is turned clockwise 

even slightly, the sound volume increases to its maximum and 
a message “VOLUME MAX” appears on the fl uorescent indi-
cator tube.

5.  When the [MASTER VOLUME] knob is turned counterclock-

wise even slightly, the sound volume decreases to its minimum 
and a message “VOLUME MIN” appears on the fl uorescent 
indicator tube.

To release from Common Test mode
1.  To release from this mode, press [

?/1

 STANDBY] button.

2.  The cold reset is enforced at the same time.

The cold reset clears all data including preset data stored in the 
EEPROM to initial conditions. Execute this mode when returning 
the set to the customer.
Procedure:
1. Press 

[

?/1

 STANDBY] button to turn on the system.

2. Press 

[

x

] button, [ENTER] button, and [

?/1

 STANDBY] but-

ton simultaneously.

3.  “COLD RESET” appears on the fl uorescent indicator tube. 

After that, the fl uorescent indicator tube becomes blank for a 
while, and the system is reset.

This mode is used to switch ON and OFF the VACS (Variable At-
tenuation Control System).
Procedure:
1. Press 

[

?/1

 STANDBY] button to turn on the system.

2. Press 

[

x

] button, [RETURN], and [DISPLAY] button simul-

taneously. The message “VACS OFF” or “VACS ON” appears 
on the fl uorescent indicator tube.

The step interval of AM channels can be toggled between 9 kHz 
and 10 kHz.
Procedure:
1. Press 

[

?/1

 STANDBY] button to turn on the system.

2.  Press [TUNER/BAND] button repeatedly to select the “AM”.
3. Press 

[

?/1

 STANDBY] button to turn off the system.

4.  Press [ENTER] button and [

?/1

 STANDBY] button simulta-

neously. The system turns on automatically. The message “AM  
9K STEP” or “AM   10K STEP” appears on the fl uorescent 
indicator tube and thus the channel step is changed.

This mode moves the optical pick-up to the position durable to 
vibration and clears all data including preset data stored in the EE-
PROM to initial conditions during the next AC-In. Use this mode 
when returning the set to the customer after repair.
Procedure:
1. Press 

[

?/1

 STANDBY] button to turn on the system.

2.  Select CD function.
3. Press 

[x] button, [OPEN/CLOSE] button and  [

?/1

 STAND-

BY] button simultaneously. The system turns off automati-
cally.

4.  After the “STANDBY” blinking display fi nishes, a message 

“MECHA LOCK” is displayed on the fl uorescent  indicator 
tube and the CD ship mode is set.